CN115070037A - Method for enhancing Ti-Al series layered composite material by utilizing AlCoCrFeNi high-entropy alloy - Google Patents

Abstract

A method for reinforcing Ti-Al series layered composite material by utilizing AlCoCrFeNi high-entropy alloy relates to a method for reinforcing Ti-Al series layered composite material. The invention aims to solve the problems of low strength, poor plasticity and poor corrosion resistance of the Ti-Al intermetallic compound prepared by the prior art. The method comprises the following steps: according to the following steps: sequentially stacking a Ti foil, an Al foil, an AlCoCrFeNi high-entropy alloy foil (AlCoCrFeNi high-entropy alloy particles), an Al foil and a Ti foil to form a unit; one or more units are stacked from bottom to top and then placed into a mold, and the mold filled with the material is placed into a vacuum hot-pressing furnace for vacuum hot-pressing sintering to obtain the AlCoCrFeNi high-entropy alloy reinforced Ti-Al series layered composite material. The invention has simple preparation process and is expected to be widely used in the fields of navigation, aerospace, civil use, medical appliances and the like.

Description

An AlCoCrFeNi high-entropy alloy reinforced Ti-Al layered composite material method

technical field

The present invention relates to a method for reinforcing Ti-Al series layered composite material.

Background technique

Intermetallic compounds have the advantages of high strength and high modulus. However, most of the intermetallic compounds have difficulty in moving dislocations during deformation at low temperatures, resulting in poor plasticity of the intermetallic compounds. Therefore, how to increase the toughness of intermetallic compounds is the main purpose of composite material design. In the mid-1990s, it was found that shells in nature have a special brittle and tough layered structure. Following the special structure of shells, the United States has developed a low-density, high-strength Ti/Al ₃ Ti layered composite material. The successful development of this material has preliminarily improved the problem of poor plasticity of intermetallic compounds, so that it not only has the high strength, high modulus and heat resistance of Al ₃ Ti, but also retains the high plasticity of the ductile material Ti. It also combines a special layered structure and a failure mechanism different from other metals.

In order to imitate the special structure of shells for material design, on the basis of the layered structure, we should learn from each other's strengths and weaknesses according to the characteristics of different materials to make up for the shortcomings of different material properties. Not only the anisotropy and heterogeneity of the material should be considered, but also the characteristics of the reinforcement, the material of the matrix, the volume fraction of the reinforcement, etc. should be determined. It is also necessary to consider which preparation process is used to achieve effective connection between the various layers of materials. Therefore, higher requirements are put forward for the design and preparation of layered composite materials.

The Ti-Al intermetallic compounds prepared by the prior art still have the problems of low strength, poor plasticity and corrosion resistance.

SUMMARY OF THE INVENTION

The purpose of the present invention is to solve the problems of low strength, poor plasticity and corrosion resistance of the Ti-Al intermetallic compounds prepared by the prior art, and to provide a kind of enhanced Ti-Al layered composite material using AlCoCrFeNi high entropy alloy. method.

The invention provides a method for preparing the AlCoCrFeNi high-entropy alloy reinforced Ti-Al layered composite material with high strength, high toughness and high corrosion resistance, which can be prepared at normal temperature, is easy to operate and has low cost. AlCoCrFeNi high-entropy alloy reinforced Ti-Al layered composites.

A method for using AlCoCrFeNi high-entropy alloy to strengthen Ti-Al series layered composite material is completed according to the following steps:

First, the Ti foil, Al foil, and AlCoCrFeNi high-entropy alloy foil were polished to remove the oxide layer on the surface, and then ultrasonically cleaned and dried. ), Al foil and Ti foil are stacked in sequence as a unit; one unit or multiple units are stacked from bottom to top and put into the mold, and then the mold with the material is put into the vacuum hot pressing furnace for Vacuum hot pressing sintering to obtain AlCoCrFeNi high-entropy alloy reinforced Ti-Al layered composite material.

The advantages of the finished material prepared by the present invention:

1. The single-phase Al ₃ Ti matrix of the AlCoCrFeNi high-entropy alloy-reinforced Ti-Al layered composite prepared by the present invention has higher elastic modulus (220GPa) and lower density than other metal matrixes, so The prepared AlCoCrFeNi high-entropy alloy reinforced Ti-Al layered composite material also includes the advantages of Al ₃ Ti matrix, and has excellent mechanical properties with high strength, low density and high modulus;

2. The AlCoCrFeNi high-entropy alloy reinforced Ti-Al layered composite material prepared by the present invention has a special layered structure similar to a shell, so it has a special failure mechanism of the laminated material, including interlayer cracking, crack deflection, brittleness Crack propagation and other mechanisms make the prepared materials have excellent impact resistance and energy absorption properties;

3. The interlayer interface of the AlCoCrFeNi high-entropy alloy reinforced Ti-Al series composite material prepared by the present invention belongs to metallurgical bonding, and the formed interface has the advantages of high bonding strength, defect-free and high quality, so that the Ti and AlCoCrFeNi with better toughness are High-entropy alloys show good toughening effect;

Fourth, the metal materials Al foil, Ti foil and AlCoCrFeNi high-entropy alloy foil (AlCoCrFeNi high-entropy alloy particles) used in the present invention are relatively easy to obtain, the preparation process and preparation process are simple, and the production cost is low;

5. Compared with ordinary metal materials, the high-entropy alloy selected in the present invention has the characteristics of short-range chemical order and lattice distortion, which makes it more advantageous in toughening. ratio to achieve the best toughening effect;

6. The AlCoCrFeNi high-entropy alloy selected in the present invention has good compatibility with the matrix Al ₃ Ti material, and the two can form a good metallurgical combination by adjusting the parameters such as temperature and pressure in the preparation process;

7. The preparation process of the invention is simple, and is expected to be widely used in the fields of navigation, aerospace, civil use, medical equipment and the like.

The invention can obtain the Ti-Al series layered composite material reinforced by the AlCoCrFeNi high-entropy alloy.

Description of drawings

Fig. 1 is the preparation flow chart of the present invention, and HEA is AlCoCrFeNi high entropy alloy in the figure;

2 is a scanning electron microscope photograph of the interface between the AlCoCrFeNi high-entropy alloy and the Al ₃ Ti matrix in the Ti-Al-based layered composite reinforced by the AlCoCrFeNi high-entropy alloy sheet prepared in Example 1;

3 is a photo of the distribution of Al elements in the AlCoCrFeNi high-entropy alloy sheet-reinforced Ti-Al layered composite material prepared in Example 1;

4 is a photo of the distribution of Ti elements in the Ti-Al-based layered composite reinforced by the AlCoCrFeNi high-entropy alloy sheet prepared in Example 1;

Fig. 5 is the position distribution of each phase of the Ti-Al layered composite material reinforced by the AlCoCrFeNi high-entropy alloy sheet prepared in Example 1;

Fig. 6 is a polarization curve diagram of high-entropy alloy (HEA) foil, Ti(TA1) foil, HEA-enhanced Ti/Al ₃ Ti layered composite, and Ti/Al ₃ Ti layered composite;

Fig. 7 is the Vickers hardness test curve of the material;

Fig. 8 is the tensile property curve of the AlCoCrFeNi high-entropy alloy particle-reinforced Ti-Al layered composite prepared in Example 2;

FIG. 9 is a SEM image of the AlCoCrFeNi high-entropy alloy particle-reinforced Ti-Al layered composite material prepared in Example 2. FIG.

Detailed ways

Embodiment 1: A method of utilizing AlCoCrFeNi high-entropy alloy to strengthen the Ti-Al layered composite material in this embodiment is completed according to the following steps:

First, the Ti foil, Al foil, and AlCoCrFeNi high-entropy alloy foil were polished to remove the oxide layer on the surface, and then ultrasonically cleaned and dried. ), Al foil and Ti foil are stacked in sequence as a unit; one unit or multiple units are stacked from bottom to top and put into the mold, and then the mold with the material is put into the vacuum hot pressing furnace for Vacuum hot pressing sintering to obtain AlCoCrFeNi high-entropy alloy reinforced Ti-Al layered composite material.

Embodiment 2: The difference between this embodiment and Embodiment 1 is that the Al foil is 1060 commercial aluminum, and the Ti foil is commercial TA1 alloy. Other steps are the same as in the first embodiment.

Embodiment 3: The difference between this embodiment and Embodiment 1 or 2 is that the content of Co in the AlCoCrFeNi high-entropy alloy foil is 23.3%, the content of Cr is 20.6%, the content of Fe is 22.1%, and the content of Ni is 23.3%. The content of 23.3%. Other steps are the same as in the first or second embodiment.

Embodiment 4: The difference between this embodiment and Embodiments 1 to 3 is that 240 mesh, 600 mesh, 800 mesh, 1200 mesh, and 2000 mesh sandpaper are used in sequence to rub Ti foil, Al foil, and AlCoCrFeNi high-entropy alloy foil respectively. Grind. Other steps are the same as those of the specific embodiments 1 to 3.

Embodiment 5: One of the differences between this embodiment and Embodiments 1 to 4 is that the thickness of the Ti foil is 0.8 mm to 1.0 mm. The other steps are the same as those in the first to fourth embodiments.

Embodiment 6: The difference between this embodiment and Embodiments 1 to 5 is that the thickness of the Al foil is 0.5 mm to 0.8 mm. Other steps are the same as those of the specific embodiments 1 to 5.

Embodiment 7: The difference between this embodiment and Embodiments 1 to 6 is that the thickness of the AlCoCrFeNi high-entropy alloy foil is 1.0 mm to 1.1 mm. Other steps are the same as those of the specific embodiments 1 to 6.

Embodiment 8: The difference between this embodiment and Embodiments 1 to 7 is that the vacuum hot pressing sintering process is: under the vacuum degree of 10 ^-3 Pa, the vacuum hot pressing furnace is heated at a specific temperature. The temperature is raised from room temperature to 540°C to 550°C and kept for a certain period of time, and then heated to 660°C to 670°C at a specific heating rate and kept warm, and finally cooled to 400°C at a specific cooling rate, and then cooled with the furnace to room temperature. Other steps are the same as those of the specific embodiments 1 to 7.

Embodiment 9: The difference between this embodiment and Embodiments 1 to 8 is that the vacuum hot pressing furnace maintains a pressure of 2 MPa to 4 MPa during the process of heating from room temperature to 540 ° C ~ 550 ° C at a specific heating rate, and at 540 ° C ~ The pressure of 2MPa~4MPa is maintained in the holding stage at 550℃, the pressure is maintained at 2MPa~4MPa during the temperature rise to 660℃~670℃ at a specific heating rate, and the pressure is maintained at 0.1MPa in the holding period of 660℃~670℃, and the temperature is cooled down to 660℃~670℃. 3MPa pressure was maintained during the process of 400°C. Other steps are the same as those of the specific embodiments 1 to 8.

Embodiment 10: The difference between this embodiment and Embodiments 1 to 9 is that the heating rate and the cooling rate are both 1°C/min～2°C/min; The time of heating is 10min～15min; the time of heating up to 660℃～670℃ and keeping the temperature is 5h～6h. Other steps are the same as those of the specific embodiments 1 to 9.

Adopt the following examples to verify the beneficial effects of the present invention:

Embodiment 1: a kind of method of utilizing AlCoCrFeNi high-entropy alloy sheet to strengthen Ti-Al series layered composite material is completed according to the following steps:

Chamfer 50×50mm×0.5mm Al foil, 0.8mm Ti foil and 1.0mm AlCoCrFeNi high-entropy alloy foil, and then use 240-mesh, 600-mesh, 800-mesh, 1200-mesh, and 2000-mesh sandpaper to rub Ti Foil, Al foil, AlCoCrFeNi high-entropy alloy foil are polished to remove the oxide layer and oil stain on the surface of the material to ensure that a clean surface layer is exposed, so that the surface is covered with scratches, and then ultrasonically cleaned, and the treated raw materials are placed in water. The cleaning time is 20min. After the cleaning is completed, put it into the ultrasonic cleaning machine filled with absolute ethanol for cleaning, the time is 15min, and then dry the raw materials after cleaning, and then follow: Ti Foil, Al foil, AlCoCrFeNi high-entropy alloy foil, Al foil and Ti foil are stacked in sequence as a unit; the two units are stacked from bottom to top and put into the mold, and then the mold with the material is put into Vacuum hot pressing sintering in a vacuum hot pressing furnace;

The Al foil is 1060 commercial aluminum, and the Ti foil is commercial TA1 alloy;

The used vacuum hot pressing sintering process is as follows: under the vacuum degree of 10 ^-3 Pa, the vacuum hot pressing furnace is heated from room temperature to 550 ° C at a heating rate of 2 ° C/min, and the pressure of 3 MPa is maintained during the heating process. Incubate at 550 °C for 10 min, keep 3MPa pressure during the heat preservation process at 550 °C, and then heat up from 550 °C to 670 °C at a heating rate of 1 °C/min, maintain 3 MPa pressure during the heating process, and keep at 670 °C for 6 hours. The pressure was maintained at 0.1 MPa during the heat preservation process at ℃, and then the temperature was lowered to 400 ℃ at a cooling rate of 2 ℃/min, and the pressure was maintained at 3 MPa during the cooling process. (Ti/Al ₃ Ti) layered composite (HEA reinforced Ti/Al ₃ Ti layered composite).

2 is a scanning electron microscope photograph of the interface between the AlCoCrFeNi high-entropy alloy and the Al ₃ Ti matrix in the Ti-Al-based layered composite reinforced by the AlCoCrFeNi high-entropy alloy sheet prepared in Example 1;

It can be seen from Figure 2 that the quality of interlayer bonding is high, there is obvious delamination, there is an obvious centerline, and there are trace cracks, which are caused by the collision between primary phases and are not It will affect the performance of the material, which can be suppressed by optimizing the preparation process; there is a reaction zone between the AlCoCrFeNi high-entropy alloy foil and the Al ₃ Ti matrix, which is produced by the reaction of the AlCoCrFeNi high-entropy alloy and Al. The interface layer has high hardness, The strength is high, and a small amount of cracks are generated; the energy spectrum analysis and XRD analysis show that the AlCoCrFeNi high-entropy alloy foil is left, so the composite material prepared under the preparation method of this embodiment better retains the AlCoCrFeNi high-entropy alloy foil. The performance of the alloy foil makes the composite material have high strength and toughness as a whole.

3 is a photo of the distribution of Al elements in the AlCoCrFeNi high-entropy alloy sheet-reinforced Ti-Al layered composite material prepared in Example 1;

4 is a photo of the distribution of Ti elements in the Ti-Al-based layered composite reinforced by the AlCoCrFeNi high-entropy alloy sheet prepared in Example 1;

The distribution of elements in the material can be clearly seen from Figures 3 and 4.

Fig. 5 is the position distribution of each phase of the Ti-Al layered composite material reinforced by the AlCoCrFeNi high-entropy alloy sheet prepared in Example 1;

After XRD analysis and EDS analysis, it can be seen that the material after the reaction is basically composed of four basic phases: Ti, Al ₃ Ti, AlCoCrFeNi, and AlCoCrFeNi+Al (two-phase region).

Fig. 6 is a polarization curve diagram of high-entropy alloy (HEA) foil, Ti(TA1) foil, HEA-enhanced Ti/Al ₃ Ti layered composite, and Ti/Al ₃ Ti layered composite;

Corrosion performance of Ti-Al layered composites reinforced by AlCoCrFeNi high-entropy alloy sheets prepared in Example 1: Through the configuration of three-electrode system, the reference electrode is Ag/AgCl electrode, the auxiliary electrode is platinum electrode, and VMP3 electrochemistry is used The workstation tests the corrosion resistance of experimental materials and experimental raw materials at room temperature of 23 °C. The following data are obtained through the test, as shown in Table 1;

Table 1

The electrochemical corrosion test in NaCl solution shows that the corrosion potential of the Ti/Al ₃ Ti layered composite reinforced by the high-entropy alloy sheet is higher than that of the Ti/Al ₃ Ti layered composite. The higher the corrosion potential, the better the corrosion resistance. the better. Therefore, the corrosion resistance of the prepared material is improved compared with that of the Ti/Al ₃ Ti layered composite material.

Fig. 7 is the Vickers hardness test curve of the material;

It can be seen from the Vickers hardness test curve in Fig. 7 that the hardness of the high-entropy alloy sheet-reinforced Ti/Al ₃ Ti layered composite material changes periodically due to the layered structure, and the highest hardness appears in the high-entropy alloy layer. The values are 882-897HV; the average hardness of the resulting Al ₃ Ti is 552HV.

The longitudinal compressive strength of the AlCoCrFeNi high-entropy alloy sheet reinforced Ti-Al layered composite material prepared in Example 1 is 1006 MPa.

Embodiment 2: A method of utilizing AlCoCrFeNi high-entropy alloy particles to strengthen the Ti-Al series layered composite material is completed according to the following steps:

Chamfer 50×50mm×0.5mm Al foil and 0.8mm Ti foil, and then use 240-mesh, 600-mesh, 800-mesh, 1200-mesh, and 2000-mesh sandpaper to grind the Ti foil and Al foil respectively to remove the material. The oxide layer and oil stain on the surface should be exposed to a clean surface layer, so that the surface is covered with scratches, and then ultrasonically cleaned, and the treated raw materials are placed in an ultrasonic cleaning machine filled with clean water for cleaning. The cleaning time is 20min. After the cleaning is completed Then put it into an ultrasonic cleaning machine filled with absolute ethanol for cleaning for 15 minutes, and then dry the raw materials after cleaning, and then follow: Ti foil, Al foil, AlCoCrFeNi high-entropy alloy particles, Al foil and Ti The foils are stacked in sequence as a unit; the two units are stacked from bottom to top and put into the mold, and then the mold with the material is put into the vacuum hot-pressing furnace for vacuum hot-pressing sintering;

The Al foil is 1060 commercial aluminum, and the Ti foil is commercial TA1 alloy;

The used vacuum hot pressing sintering process is as follows: under the vacuum degree of 10 ^-3 Pa, the vacuum hot pressing furnace is heated from room temperature to 550 ° C at a heating rate of 2 ° C/min, and the pressure of 3 MPa is maintained during the heating process. Incubate at 550 °C for 10 min, keep 3 MPa pressure during the heat preservation process at 550 °C, and then heat up from 550 °C to 660 °C at a heating rate of 1 °C/min, maintain 3 MPa pressure during the heating process, and keep at 660 °C for 6 hours. The pressure was maintained at 0.1 MPa during the heat preservation process at ℃, and then cooled to 400 ℃ at a cooling rate of 2 ℃/min. During the cooling process, the pressure was maintained at 3 MPa, and finally cooled to room temperature with the furnace to obtain AlCoCrFeNi high entropy alloy particles. Laminated composites.

Fig. 8 is the tensile property curve of the AlCoCrFeNi high-entropy alloy particle-reinforced Ti-Al layered composite prepared in Example 2;

It can be seen from Figure 8 that the average elongation at break of the AlCoCrFeNi high-entropy alloy particle-reinforced Ti-Al layered composite prepared in Example 2 is 40.61%, which is higher than 4.2% of Al ₃ Ti, showing good plasticity deformability.

9 is a SEM image of the AlCoCrFeNi high-entropy alloy particle-reinforced Ti-Al-based layered composite prepared in Example 2;

It can be seen from Fig. 9 that the prepared material has obvious delamination phenomenon, the structure is dense, and there is no obvious defect.

The compressive strength of the AlCoCrFeNi high-entropy alloy particle-reinforced Ti-Al-based layered composite prepared in Example 2 in the vertical stacking direction is 490 MPa.

Claims (10)

1. A method for enhancing Ti-Al series layered composite material by utilizing AlCoCrFeNi high-entropy alloy is characterized by comprising the following steps:

firstly, respectively polishing Ti foil, Al foil and AlCoCrFeNi high-entropy alloy foil to remove an oxide layer on the surface, then ultrasonically cleaning, drying, and then, according to the following steps: sequentially stacking a Ti foil, an Al foil, an AlCoCrFeNi high-entropy alloy foil (AlCoCrFeNi high-entropy alloy particles), an Al foil and a Ti foil to form a unit; one or more units are stacked from bottom to top and then placed into a mold, and the mold filled with the material is placed into a vacuum hot-pressing furnace for vacuum hot-pressing sintering to obtain the AlCoCrFeNi high-entropy alloy reinforced Ti-Al series layered composite material.

2. The method for reinforcing the Ti-Al series layered composite material by using the AlCoCrFeNi high-entropy alloy as claimed in claim 1, wherein the Al foil is 1060 commercial aluminum, and the Ti foil is commercial TA1 alloy.

3. The method for reinforcing the Ti-Al layered composite material by using the AlCoCrFeNi high-entropy alloy plate as claimed in claim 1, wherein the AlCoCrFeNi high-entropy alloy foil contains 23.3% of Co, 20.6% of Cr, 22.1% of Fe and 23.3% of Ni.

4. The method for enhancing the Ti-Al series layered composite material by utilizing the AlCoCrFeNi high-entropy alloy as claimed in claim 1, wherein the Ti foil, the Al foil and the AlCoCrFeNi high-entropy alloy foil are respectively polished by using 240-mesh, 600-mesh, 800-mesh, 1200-mesh and 2000-mesh sandpaper in sequence.

5. The method for reinforcing the Ti-Al layered composite material by using the AlCoCrFeNi high-entropy alloy as claimed in claim 1, wherein the thickness of the Ti foil is 0.8 mm-1.0 mm.

6. The method for reinforcing the Ti-Al layered composite material by using the AlCoCrFeNi high-entropy alloy as claimed in claim 1, wherein the thickness of the Al foil is 0.5mm to 0.8 mm.

7. The method for reinforcing the Ti-Al layered composite material by using the AlCoCrFeNi high-entropy alloy as claimed in claim 1, wherein the thickness of the AlCoCrFeNi high-entropy alloy foil is 1.0-1.1 mm.

8. The method for enhancing the Ti-Al series layered composite material by utilizing the AlCoCrFeNi high-entropy alloy as claimed in claim 1, wherein the vacuum hot-pressing sintering process comprises the following steps: at 10 ^-3 And (2) under the vacuum degree of Pa, heating the vacuum hot-pressing furnace from room temperature to 540-550 ℃ at a specific heating rate, preserving heat, heating to 660-670 ℃ at the specific heating rate after preserving heat for a certain time, preserving heat, cooling to 400 ℃ at the specific cooling rate, and cooling to room temperature along with the furnace.

9. The method of claim 8, wherein the pressure of 2MPa to 4MPa is maintained in the vacuum autoclave during the temperature increase from room temperature to 540 ℃ to 550 ℃ at a specific temperature increase rate, the pressure of 2MPa to 4MPa is maintained in the temperature preservation stage at 540 ℃ to 550 ℃, the pressure of 2MPa to 4MPa is maintained during the temperature increase to 660 ℃ to 670 ℃ at a specific temperature increase rate, the pressure of 0.1MPa is maintained in the temperature preservation stage at 660 ℃ to 670 ℃, and the pressure of 3MPa is maintained during the temperature decrease to 400 ℃ at a specific temperature decrease rate.

10. The method for enhancing the Ti-Al series layered composite material by utilizing the AlCoCrFeNi high-entropy alloy as claimed in claim 8, wherein the temperature rise rate and the temperature decrease rate are both 1 ℃/min to 2 ℃/min; heating to 540-550 ℃ and keeping the temperature for 10-15 min; the temperature is raised to 660-670 ℃ and the heat preservation time is 5-6 h.

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